Same problem here since the update in both xmms and mplayer when either uses
alsa for audio. Switching either over to oss and life is good again.
I'm using snd_intel8x0 for sound on an 'nVidia Corporation nForce2 AC97 Audio
Controler'

also, i'm using 2.6.14-1.1644_FC4 (x86) with XFCE as my window manager.
Someone else I know is also hitting this problem with KDE, but i don't have
specifics on his hardware or configuration, other than alsa audio stopped
working after the update today.

I have a similar problem, although I do not think dmix is involved. I do not
have a ~/.asoundrc file. I use kde from kde-redhat, currently kde-3.5.0, and
cannot use ALSA anymore as the sound server since upgrading ALSA. Prior to the
update sound worked fine. I can, however, use OSS.
FWIW:
$ ll /etc/alsa/pcm/dmix.conf /etc/alsa/pcm/dsnoop.conf
-rw-r--r-- 1 root root 1111 Dec 9 08:19 /etc/alsa/pcm/dmix.conf
-rw-r--r-- 1 root root 1117 Dec 9 08:19 /etc/alsa/pcm/dsnoop.conf
$ cat ~/.asoundrc
cat: /home/dad/.asoundrc: No such file or directory
$ locate asoundrc
/usr/share/doc/alsa-lib-1.0.10/asoundrc.txt
and:
$ rpm -qa|grep alsa
alsa-lib-1.0.10-2.FC4
alsa-utils-1.0.10-1.FC4
alsa-lib-devel-1.0.10-2.FC4
I use a soundblaster emu10k1 sound card/driver.
Based on a recommendation of a fellow kde-redhat user, I did:
ln -s /etc/alsa/ainit.conf /usr/share/alsa/
ln -s /etc/alsa/alsa.conf /usr/share/alsa/
and ainit $MY_USER start
But after that, ALSA still fails. Prior to that, however, kmix and amarok
would crash, even when using OSS. Afterwards, kmix and amarok ran fine under
OSS.
BTW, I'm the KDE user referenced in comment #5...

I have the same issue. ie. sound system stops working after update to
alsa-lib-1.0.10-2.FC4 with dmixed snd_intel8x0 device. After reboot will work
for a random period of time, but sound will always stop working sooner or
later. Have reverted to alsa-lib-1.0.9rf-2.FC4 and left amarok playing for 24
hours and do not have the issue.

[clivem@fedora:/etc/alsa]$ rpm -q alsa-lib
alsa-lib-1.0.10-1.FC4.test
[clivem@fedora:/etc/alsa]$ aplay
ALSA lib pcm_dmix.c:1101:(_snd_pcm_dmix_open) The field ipc_gid must be a
valid group (create group audio)
aplay: main:544: audio open error: Invalid argument
This is because dmix.conf has 'ipc_gid audio' and audio group does not exist
on my system?

(In reply to comment #19)
> This is because dmix.conf has 'ipc_gid audio' and audio group does not exist
> on my system?
>
Yes. Please remove this line from /etc/alsa/pcm/dmix.conf and
/etc/alsa/pcm/dsnoop.conf files.
This new test package doesn't have any RH patches, it's only clear upstream
package for driver which is included in the current FC4 kernel.

OK, tested it. ALSA now works. Well, it produces sound. alsamixer segfaults when
run from the command line. After the segfault, the console behaves wierdly, as
if some control characters were sent and the screwed things up, and needs to be
"reset."
If I run alsamixer from a virtual terminal (Ctrl-Alt-F1), the following (or a
portion thereof -- it's not consistent) occasionally will get displayed at the
top of the screen:
"alsamixer: relocation error: alsamixer: symbol snd_mixer_selem_get_playback_dB,
version ALSA_0.9 not defined in file libasound.so.2 with link time reference
Kernel 2.6.14-1.1653_FC4 on an i686"
$ locate libasound.so.2
/lib/libasound.so.2
/lib/libasound.so.2.0.0
/usr/lib/libasound.so.2.0.0
/usr/lib/libasound.so.2
hmmm...
$ rpm -qf /lib/libasound.so.2
alsa-lib-1.0.10-2.FC4
$ rpm -qf /usr/lib/libasound.so.2
libasound2-1.0.9rf-21.rhfc2.at
After removing libasound2-1.0.9rf-21.rhfc2.at, alsamixer works :)
Must be a remnant of my upgrade from FC2. When alsa 1.0.9 was installed by the
upgrade, it didn't matter that the ATrpms version for FC2 was still around. But
after the update to 1.0.10, that did matter. It's a wonder alsa *ever* worked on
my system (it did, honestly...). Didn't hlep the troubleshooting process to have
the ATrpms' alsa be called libasound2 while FC4's is alsa-lib...